The Local Boundary Detection Model (LBDM) and its Application in the Study of Expressive Timing

In this paper two main topics are addressed. Firstly, the Local Boundary Detection Model (LBDM) is described; this computational model enables the detection of local boundaries in a melodic surface and can be used for musical segmentation. The proposed model is tested against the punctuation rule system developed by Friberg et al. (1998) at KTH, Stockholm. Secondly, the expressive timing deviations found in a number of expert piano performances are examineded in relation to the local boundaries discovered by LBDM. As a result of a set of preliminary experiments, it is suggested that the assumption of final-note lengthening of a melodic gesture is not always valid and that, in some cases, the end of a melodic group is marked by lengthening the second-to-last note (or, seeing it from a different viewpoint, by delaying the last note).